1. Field of the Invention
The present invention relates generally to a printed circuit board connecting and locking assembly and, more particularly, to an assembly for use in conjunction with zero insertion force connectors.
2. Description of the Prior Art
Computer technology has made extensive use of printed circuit boards for mounting complete modular circuits. However, conventional circuit board connectors posed problems due to the excessive amount of force required for effectuating the connection between the printed circuit board and the connector. To avoid these problems, zero or low insertion force connectors (hereinafter ZIF connectors) have been developed which impose substantially no force upon the electrical contacts of the circuit board and connector during insertion of the printed circuit board into electrical engagement with the ZIF connector. U.S. Pat. No. 4,076,362 is representative of one of the large number of such ZIF connectors.
While such ZIF connectors have proven greatly advantageous over conventional plug-in contacts, they have not been without problems themselves. In many installations, it is difficult, if not impossible, to visually determine whether or not the ZIF connector is in its open position, its closed position, or some position inbetween. This can result in damage to the printed circuit board if an attempt is made to insert it into a closed ZIF connector or can result in disengagement of the electrical contacts if the disconnector is not properly closed after insertion of the circuit board. Furthermore, since the electrical contacts are not clearly visible in ZIF connectors and since they are often capable of accepting various contact arrangements, a problem results in that a technician could inadvertently install the wrong circuit board in a particular connector.
To avoid the problem of a circuit board becoming disengaged from its connector, various circuit board locking clips and connector arrangements are known such as from U.S. Pat. Nos. 4,017,138; 3,970,353; and 3,954,242, while U.S. Pat. No. 3,853,379 shows a printed circuit board connector assembly wherein circuit board locking latches are connected to an actuating rod for opening and closing ZIF connector contacts so as to enable insertion and withdrawal of the printed circuit board into and out of the contacts of the ZIF connector only when they are in their open or inactive position.
However, none of these above-noted patents describe a printed circuit board connecting and locking assembly which is able to ensure that only the correct circuit board is inserted into a particular ZIF connector in a simple manner while still achieving all of the beneficial attributes of such arrangements with respect to secure fastening of the circuit board in place and ensuring that insertion and withdrawal of the circuit board occurs only when the ZIF connectors are in their open position.